In treating toilet flush water with chemicals in order to produce desirable effects such as bowl aesthetics, cleaning, disinfection, deodorization, aerosol reduction, etc., it is desirable that the chemicals be dispensed into the flush water automatically each time the toilet is flushed. The prior art discloses numerous devices which have been designed for this purpose.
Particularly desirable devices are those comprising a solid cake composition. In this type of device a measured amount of water enters the device during one flush cycle and remains in contact with the cake between flushes, thereby forming a concentrated solution of the composition which is dispensed into the flush water during the next flush. The advantages of such devices are hat the chemical composition can be packaged and shipped in more concentrated form than aqueous solutions of the chemicals. Also, the problems of liquid spillage resulting from breakage of the dispensers during shipment or handling is eliminated.
Prior art surfactant cake compositions are disclosed in U.S. Pat. No. 4,308,625, Kitko, issued Jan. 5, 1982 and U.S. Pat. No. 4,043,931, Jeffrey et al, issued Aug. 23, 1977. These patents disclose a lavoratory cleansing tablet which is formed with two or more nonionic surfactants which includes the use of polyalkoxylated alcohols. U.S. Pat. No. 4,477,363, Wong et al, issued Oct. 16, 1984, discloses a solid cake comprising free fatty alcohol and a buffered alkali earth metal alky sulfate surfactant. U.S. Pat. No. 4,310,434, Choy et al, issued Jan. 12, 1982; and U.S. Pat. No. 4,278,571, Choy, issued July 14, 1981, entitled "Surfactant Cake Compositions", all of which are incorporated herein by reference, disclose surfactant cake compositions containing dyes and perfumes which may be utilized in the present invention. The surfactants provide cleaning and sudsing in the toilet bowl and also serve to dispense other components of the compositions such as dyes, perfumes, organic resins, etc.
U.S. Pat. No. 4,460,490 discloses the use of natural gums in combination with fatty alcohol ethoxylates. However, guar gum and polyethylene oxide homopolymers which produced the synergism in the present invention are not disclosed.
The polyethylene oxide hompolymers which are utilized in the present invention are commercially available and sold by Union Carbide Corp. under the trademark POLYOX. The POLYOX resins are high polymers with the common structure: --O--CH.sub.2 CH.sub.2 --.sub.n. The degree of polymerization, n, varies from about 2,000 to about 100,000, depending upon the viscosity grade of resin.
POLYOX resins are non-ionic and undergo the normal salting-out effects associated with neutral molecules in solutions of high dielectric media. Salting-out effects manifests themselves in depressing the upper temperature limit of solubility and in reducing the viscosity of both dilute and concentrated solutions of the polymers.
Water-soluble inert salts such as alkali metal chlorides and sulfates are normally used in such compositions to act as a "filler" so that the composition can be formed into cakes of desirable size without using excessive amounts of active ingredients. The predominant ingredients of the cake compositions are usually the surfactant, perfume and the filler salt.
In U.S. Pat. No. 4,722,801 of Bunczk et al, which is herein incorporated by reference, there is disclosed the synergism which occurs in the combination of guar gum and sodium chloride.
A major problem in prior art has been short and/or erratic longevity of surfactant cakes because of rapid and/or uneven dissolution resulting in decreased cake stability and longevity.
It has been found that a solid cake composition having a long and uniform block life can be provided where the composition includes the combination of guar gum and polyethylene oxide homopolymer together with the conventional materials such as surfactants, fillers, binders, dyes, fragrances, extenders and the like.
It has been further found that cross-linking of guar gum with a calcium ion further extends the life of the composition.
It is an object of the present invention to provide a solid cake compositions which includes the combination of guar gum and polyethylene oxide homopolymers, which compositions are suitable for use for automatically dispensing cleaning agents into the toilet.
It is a further object of the present invention to increase the cake life by the cross-linking of the guar gum with a calcium salt.
It is a still further object of the present invention to provide a lavoratory block which has a long and uniform block life.
Other objects, advantages and novel features of the present invention will be apparent to those skilled in the art from the following description and appended claims.